IN SITU STUDIES OF CHEMICALLY MEDIATED FEEDING BY DEEP-SEA FISHES AND A MIDWATER HYDROMEDUSA

Chemoreception is believed to be a key sensory system for animals inhabiting the deep-sea. Little is known, however, about the chemical ecology of these species because of the difficulties collecting healthy specimens and conducting field experiments. Through the use of remotely operated vehicles (ROVs), we are now able to examine chemically mediated feeding behaviors of pelagic and benthic organisms in these vast environments. This talk will present examples of two such studies.
Deep-sea fishes use olfaction to locate food. How they navigate to odor sources, however, is unclear. We found that species attracted by a bait solution at depths of 300 - 3000 m utilized rheotaxis, chemotaxis, and geotaxis. Interestingly, whether the fish had bilateral (e.g. rattails) or single (e.g. hagfish) sensory structures, all either zigzagged and cast through plume edges, or moved directly up plume centers.
Gelatinous zooplankton are an integral part of midwater ecosystems. Most are thought to be passive